Transmitting apparatus.



H. SHOEMAKER. TRANSMITTING APPARATUS. APPLICATION FILED AUG. 30, 1907.

I a-Qumm P tented May 11,1909.

HARRY SHOEMAIi-ER, OF JERSEY CITY, NEW JERSEY.

TRANSMITTING APPARATUS.

Specification of Letters Patent.

Patented May 11, 1909.

Application filed August 30, 1907. Serial No. 390,814.-

To all whom it may concern: I

Beitknown that I, HARRY SHOEMAKER, a citizen of the United States,residing at Jersey City, county of Hudson, State of New Jersey, haveinvented certain new and useful Improvements in Trans pitting Apparatus,of which the following is a specification.

My invention relates to transmitting apparatus, andpartioularly totransmitting apparatus for use in a signaling system wherein the energyistransmitted 1n electro-radiant form through the natural media.

It is the object of my invent-ion to produce transmitting apparatus ofthe class described, in which a relatively great amount of electricalenergymay be converted into high frequency energy, a storage device,such as a condenser, being employed to receive a charge from anysuitable source and to be allowed to dischar e in an oscillatingcircuit, having a natural igh frequency, such circuit containing one ormore condensers'or storage devices other than that in communication withthecharging source. By such an arrangement, a relatively large chargecanbe drawn from the charging source, and in the case of high powertransnitters, the condensers are so disposed that, while a great amountof energy may be absorbed from the char ing source, yet the naturalperiod of the oscillation circuit may be suitably high.

My invention resides in the features hereinafter described and claimed.

For an illustration of several of the forms my invention may take,particularly when employed in a telegraphic transmitter, reference is tobehad to the accompanying drawing, in which:

i ure 1 is a diagrammatic view illustrating the circuits of thetransmitting apparatus embodying my invention. Fig. 2 1s a diagrammaticview of a modified form my invention may take.

Referring to Fig. 1., between the aerial conductor A and the earth orother suitable connection E is serially connected 2. variable portion ofthe inductance L, which may take the form of a helix, or other suitableform. Connected in shunt to a variable portion of the inductance L, is acircuit including the spark gap g and the condensers K and K.

In shunt to one of the condensers, as for example, K, is connected thesecondary S of a step-u'p transformer whose primary I is connected incircuit with a suitable source of fluctuating or alternating current, asG, and

the operators key k. The condensers K and K are preferably, though notnecessarily, of equal capacities. As to the oscillation circuit, L, 9,K- and K the condensers K and K are connected in series with each otherand, therefore, the capacity of that oscillation circuit is, when thecondensers are of equal capacities, one-half the capacity of either one.But inasmuch as only one of the condensers is connected to the secondaryS of the charging transformer, the capacity as to the circuit includingthe secondary S is twice the capacity in the. oscillation circuit. Inconsequence, the condenser K, at a iven potential of the secondary S,will a sorb twice as great a charge as in the case where all thecondensers of the oscillation circuit are subjected to the secondarypotential. This arrangement, therefore, affords means for absorbing avery great amount of energy from the charging source, while the naturalfrequency of the oscillation circuit is still maintained as high asnecessary or desired. Thus, in high power transmitters it has beennecessary to use very high charging potentials in order to store enoughenergy in the capacities or condensers, which capacities werenecessarily small in order that the natural fre uency of the oscillationcircuit might be su' ciently high. It is preferred also that thecondenser K be of such capacity that the circuit containing thecondenser K and the secondary S of the transformer, should be resonantor approximately resonant for the frequency of the current passingthrough the primary P. In such case, the condenser K will absorb a verygreat or maximum charge even though the potential of the secondary S isnot excessively high. By the arrangement shown, therefore, the naturalfrequency of the oscillation circuit is maintained high and as high asdesired or necessary, while the amount of energy surging in it isgreater than heretofore because of the greater charge-which will beabsorbed by the single condenser instead of the plurality of condensersin series across the secondary. It follows that while the frequency maybe maintained as high as necessary or desired in the oscillationcircuit, for high power transmitters the secondary need not supply ashigh a potential as heretofore practiced. Furthermore, the condenser Koperates as a restraining means and prevents any arc cffect originatingor existing in the gap g from heavy charge to current derived from thesecondary S, thus, making the spark at 9 more abrupt and distinctly aspark as distin uished from an arc.

The operation is as fo ows: The operator manipulates the key k in thewell known manner to roduce dots and dashes; when the key is c osed the.secondary S sup lies a the condenser K an when it is charged a s arkwill leap at g and the condenser K then discharge its great chargethrough the oscillation circuit as pre- Viousl traced, the naturalfrequency being, as .we understood in the art, determined by i thecapacity. andinductance of that circuit.

In Fig. 2, three condensers K, K and K are shown serially connected inthe osoillation circuit, while two of them, K and K are shown connectedin series with each other across the terminals of the secondary S. The'principle is the same as described in connection with Fig. 1; or, ifdesired, the secondary S may be bridged by the condenser K only in whichcase, the connection from the lower terminal of the secondary S wouldthe oscillation circuit.

ferent numbers of condensers may be 1nbe made as shown by the dottedconnection a. In such case, there 'would be two condensers in seriesbesides the condenser in In other Words, difcluded in series in theoscillation circuit and different numbers may be bridged across thesecondary S. In any case, however, the capacity subjected to thesecondary S is al- .ways greater than the effective capacity asdetermining the natural frequency of the oscillation circuit.

Where I have shown single condensers K,

' K and K, in both figures of the drawing, it

is to be understood that such condensers may be a single condenser ormay be a plurality ofcondensers in parallel. In practice, a convenientform of constructing such condensers is a plurality of Leyden jars'ortubes connected in parallel with each other.

for controlling the energy radiate it is to be understood that any othersiglpaling instruconnected inseries with each other and in series withinductance, a charging source,

' and a direct connection from said char ing source to the terminals ofless than the W iole number of capacities in said oscillation circuit. Iv

2. In transmitting apparatus, the combination with a radiatlngconductor, of anoscillation circuit associated therewith, a lurality ofcondensersserially connecte in 'said oscillation circuit and cooperatingto determine the period of said circuit, a source of While I have hereshown a telegraphic key energy, and a direct connection from said sourceof energy to the terminals of less than thewholenumber of condensersconnected in said oscillation circuit, and a signaling in strument.

In transmitting apparatus, the combination with a radiating conductor,of a plurality of condensers serially connected and operating todetermine the frequency of the radiated energy, a source of energy, adirect connection from said source of energy to the terminals of lessthan the whole number of said condensers,-and a signaling instrument.

4. In transmitting apparatus, the combi-' nation with a radiatingconductor, of a closed oscillation circuit including a sparkgap,inductance, and a plurality of capacities," all said capacitiescooperating to determine the:

period of said circuit, a source of energy, and p a connection from saidsource of energy to the terminals of less than the whole number jcircuit.

5. In transmitting apparatus, the combination with a radiatingconductor, of inductof capacities connected in said oscillation anceincluded therein, a closed oscillation" circuit including saidinductance, a spark gap and a plurality of condensers, all saidcapacities cooperating ,to determinethe period of said circuit, a sourceof energy, an a connection from said source of energy to the to theterminals ofless than the whole number of condensers. 7In transmittingapparatus, the combination with a radiating conductor, of an oscillator,said oscillator comprising a plurality of frequency determiningcondensers and a spark gap all serially connected, a source of energy,and a connection from said source of energy to the terminals of lessthan the whole num er of condensers.

' 8. In transmittin apparatus, an oscillator comprising a plurality offre uency determining condensers and a sparr gapall serially connectedwith each other, a source of energy, and aconnection from said'source tothe terminals of less than the' whole number of condensers.

In testimony whereof I have. hereunto affixed my signature in thepresence of the two subscribing witnesses.

- HARRY SHGIZQMAKER. Witnesses ANNA E. STEINBOCK, JAMn's M. SAWYER.

